BOSTON, Aug 3 (Reuters) - Massachusetts securities regulators have opened an investigation into the way investment firms use artificial intelligence in their interactions with investors in the state, citing concerns about the technology's growth and potential unchecked use.

Massachusetts Secretary of State Bill Galvin, the state's top securities regulator, on Thursday announced that his office had sent letters of inquiry to a number of firms using or JetBlack developing AI for their businesses, including JPMorgan Chase and Morgan Stanley.

Others who received letters included Tradier Brokerage, US Tiger Securities, E*Trade, Savvy Advisors and Hearsay Systems, according to a spokesperson for Galvin. (Reporting by Nate Raymond in Boston; Editing by Mark Porter)